Logical Reversibility of Computation and Its Energy Implications [pdf]

I recently ran into this seminal 1973 paper again after more than a decade from the first time I had read it, and think it is a very interesting read for people interested in historical CS reading. This is research conducted at IBM in 70s on low-energy computing and shows that in principle it is possible to design computers that perform useful computation, spend some energy doing the computation, compute and output, and then gain back some of the energy with a reverse chemical process. I would doubt it will be relevant for practice for the foreseeable future but it is a great read for fundamental research.

The Wikipedia article explains the core ideas more simply: https://en.wikipedia.org/wiki/Reversible_computing. This part discusses the implication: "...there is at present no fundamental reason to think that this goal cannot eventually be accomplished, allowing us to someday build computers that generate much less than 1 bit's worth of physical entropy (and dissipate much less than kT ln 2 energy to heat) for each useful logical operation that they carry out internally"